How to edit multiple meshes once without joining?
I think i know what you want to achieve.

If you're trying to add a rounded edge to an extruded svg text/shape, then you can simply extrude the entire mesh and use Bevel tool (Ctrl+B in Edit mode with adjacent edges selected). If using it in Edit mode, the tool is interactive, i.e. change parameters while it's active.

Alternatively, before extruding change the Pivot Point to Individual Origins in the 3D Viewport Header bar (by default, in the bottom of the 3D viewport).